Exceptionally Uniform and Scalable Multilayer MoS2 Phototransistor Array Based on Large-Scale MoS2 Grown by RF Sputtering, Electron Beam Irradiation, and Sulfurization

ACS Appl Mater Interfaces. 2020 May 6;12(18):20645-20652. doi: 10.1021/acsami.0c02393. Epub 2020 Apr 24.

Abstract

Two-dimensional molybdenum disulfide (MoS2) has emerged as a promising material for optoelectronic applications because of its superior electrical and optical properties. However, the difficulty in synthesizing large-scale MoS2 films has been recognized as a bottleneck in uniform and reproducible device fabrication and performance. Here, we proposed a radio-frequency magnetron sputter system, and post-treatments of electron beam irradiation and sulfurization to obtain large-scale continuous and high-quality multilayer MoS2 films. Large-area uniformity was confirmed by no deviation of electrical performance in fabricated MoS2 thin-film transistors (TFTs) with an average on/off ratio of 103 and a transconductance of 0.67 nS. Especially, the photoresponsivity of our MoS2 TFT reached 3.7 A W-1, which is a dramatic improvement over that of a previously reported multilayer MoS2 TFT (0.1 A W-1) because of the photogating effect induced by the formation of trap states in the band gap. Finally, we organized a 4 × 4 MoS2 phototransistor array with high photosensitivity, linearity, and uniformity for light detection, which demonstrates the great potential of 2D MoS2 for future-oriented optoelectronic devices.

Keywords: MoS2; electron beam irradiation; phototransistor array; sputtering; sulfurization.